[ 12/45] sparc: tsb must be flushed before tlb

From: Greg Kroah-Hartman
Date: Fri Jul 26 2013 - 17:08:12 EST


3.0-stable review patch. If anyone has any objections, please let me know.

------------------

From: Dave Kleikamp <dave.kleikamp@xxxxxxxxxx>

This fixes a race where a cpu may re-load a tlb from a stale tsb right
after it has been flushed by a remote function call.

I still see some instability when stressing the system with parallel
kernel builds while creating memory pressure by writing to
/proc/sys/vm/nr_hugepages, but this patch improves the stability
significantly.

Signed-off-by: Dave Kleikamp <dave.kleikamp@xxxxxxxxxx>
Acked-by: Bob Picco <bob.picco@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/sparc/mm/tlb.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/sparc/mm/tlb.c
+++ b/arch/sparc/mm/tlb.c
@@ -115,8 +115,8 @@ no_cache_flush:
}

if (!tb->active) {
- global_flush_tlb_page(mm, vaddr);
flush_tsb_user_page(mm, vaddr);
+ global_flush_tlb_page(mm, vaddr);
goto out;
}



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